Upgrade libpng to 1.2.44 for security fixes.

Change-Id: Iae257ca6ea7031a99f38e9de196d71ef8b94f9aa

1 files changed, 111 insertions, 70 deletions

diff --git a/pngwutil.c b/pngwutil.c
index cd0d3d3..c75f53e 100644
--- a/pngwutil.c
+++ b/pngwutil.c
@@ -1,8 +1,8 @@
 
 /* pngwutil.c - utilities to write a PNG file
  *
- * Last changed in libpng 1.2.37 [June 4, 2009]
- * Copyright (c) 1998-2009 Glenn Randers-Pehrson
+ * Last changed in libpng 1.2.43 [February 25, 2010]
+ * Copyright (c) 1998-2010 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
  *
@@ -12,6 +12,7 @@
  */
 
 #define PNG_INTERNAL
+#define PNG_NO_PEDANTIC_WARNINGS
 #include "png.h"
 #ifdef PNG_WRITE_SUPPORTED
 
@@ -102,9 +103,11 @@ png_write_chunk_start(png_structp png_ptr, png_bytep chunk_name,
 
    png_debug2(0, "Writing %s chunk, length = %lu", chunk_name,
       (unsigned long)length);
+
    if (png_ptr == NULL)
       return;
 
+
    /* Write the length and the chunk name */
    png_save_uint_32(buf, length);
    png_memcpy(buf + 4, chunk_name, 4);
@@ -191,7 +194,7 @@ png_text_compress(png_structp png_ptr,
 
    if (compression >= PNG_TEXT_COMPRESSION_LAST)
    {
-#if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
+#if defined(PNG_STDIO_SUPPORTED) && !defined(_WIN32_WCE)
       char msg[50];
       png_snprintf(msg, 50, "Unknown compression type %d", compression);
       png_warning(png_ptr, msg);
@@ -398,6 +401,7 @@ png_write_IHDR(png_structp png_ptr, png_uint_32 width, png_uint_32 height,
    png_byte buf[13]; /* Buffer to store the IHDR info */
 
    png_debug(1, "in png_write_IHDR");
+
    /* Check that we have valid input data from the application info */
    switch (color_type)
    {
@@ -409,7 +413,8 @@ png_write_IHDR(png_structp png_ptr, png_uint_32 width, png_uint_32 height,
             case 4:
             case 8:
             case 16: png_ptr->channels = 1; break;
-            default: png_error(png_ptr, "Invalid bit depth for grayscale image");
+            default: png_error(png_ptr,
+                         "Invalid bit depth for grayscale image");
          }
          break;
       case PNG_COLOR_TYPE_RGB:
@@ -457,7 +462,7 @@ png_write_IHDR(png_structp png_ptr, png_uint_32 width, png_uint_32 height,
     * 5. The color_type is RGB or RGBA
     */
    if (
-#if defined(PNG_MNG_FEATURES_SUPPORTED)
+#ifdef PNG_MNG_FEATURES_SUPPORTED
       !((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
       ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE) == 0) &&
       (color_type == PNG_COLOR_TYPE_RGB ||
@@ -485,7 +490,7 @@ png_write_IHDR(png_structp png_ptr, png_uint_32 width, png_uint_32 height,
    png_ptr->bit_depth = (png_byte)bit_depth;
    png_ptr->color_type = (png_byte)color_type;
    png_ptr->interlaced = (png_byte)interlace_type;
-#if defined(PNG_MNG_FEATURES_SUPPORTED)
+#ifdef PNG_MNG_FEATURES_SUPPORTED
    png_ptr->filter_type = (png_byte)filter_type;
 #endif
    png_ptr->compression_type = (png_byte)compression_type;
@@ -575,8 +580,9 @@ png_write_PLTE(png_structp png_ptr, png_colorp palette, png_uint_32 num_pal)
    png_byte buf[3];
 
    png_debug(1, "in png_write_PLTE");
+
    if ((
-#if defined(PNG_MNG_FEATURES_SUPPORTED)
+#ifdef PNG_MNG_FEATURES_SUPPORTED
         !(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) &&
 #endif
         num_pal == 0) || num_pal > 256)
@@ -604,7 +610,7 @@ png_write_PLTE(png_structp png_ptr, png_colorp palette, png_uint_32 num_pal)
 
    png_write_chunk_start(png_ptr, (png_bytep)png_PLTE,
      (png_uint_32)(num_pal * 3));
-#ifndef PNG_NO_POINTER_INDEXING
+#ifdef PNG_POINTER_INDEXING_SUPPORTED
    for (i = 0, pal_ptr = palette; i < num_pal; i++, pal_ptr++)
    {
       buf[0] = pal_ptr->red;
@@ -613,7 +619,9 @@ png_write_PLTE(png_structp png_ptr, png_colorp palette, png_uint_32 num_pal)
       png_write_chunk_data(png_ptr, buf, (png_size_t)3);
    }
 #else
-   /* This is a little slower but some buggy compilers need to do this instead */
+   /* This is a little slower but some buggy compilers need to do this
+    * instead
+    */
    pal_ptr=palette;
    for (i = 0; i < num_pal; i++)
    {
@@ -634,6 +642,7 @@ png_write_IDAT(png_structp png_ptr, png_bytep data, png_size_t length)
 #ifdef PNG_USE_LOCAL_ARRAYS
    PNG_IDAT;
 #endif
+
    png_debug(1, "in png_write_IDAT");
 
    /* Optimize the CMF field in the zlib stream. */
@@ -688,13 +697,15 @@ png_write_IEND(png_structp png_ptr)
 #ifdef PNG_USE_LOCAL_ARRAYS
    PNG_IEND;
 #endif
+
    png_debug(1, "in png_write_IEND");
+
    png_write_chunk(png_ptr, (png_bytep)png_IEND, png_bytep_NULL,
      (png_size_t)0);
    png_ptr->mode |= PNG_HAVE_IEND;
 }
 
-#if defined(PNG_WRITE_gAMA_SUPPORTED)
+#ifdef PNG_WRITE_gAMA_SUPPORTED
 /* Write a gAMA chunk */
 #ifdef PNG_FLOATING_POINT_SUPPORTED
 void /* PRIVATE */
@@ -707,6 +718,7 @@ png_write_gAMA(png_structp png_ptr, double file_gamma)
    png_byte buf[4];
 
    png_debug(1, "in png_write_gAMA");
+
    /* file_gamma is saved in 1/100,000ths */
    igamma = (png_uint_32)(file_gamma * 100000.0 + 0.5);
    png_save_uint_32(buf, igamma);
@@ -723,6 +735,7 @@ png_write_gAMA_fixed(png_structp png_ptr, png_fixed_point file_gamma)
    png_byte buf[4];
 
    png_debug(1, "in png_write_gAMA");
+
    /* file_gamma is saved in 1/100,000ths */
    png_save_uint_32(buf, (png_uint_32)file_gamma);
    png_write_chunk(png_ptr, (png_bytep)png_gAMA, buf, (png_size_t)4);
@@ -730,7 +743,7 @@ png_write_gAMA_fixed(png_structp png_ptr, png_fixed_point file_gamma)
 #endif
 #endif
 
-#if defined(PNG_WRITE_sRGB_SUPPORTED)
+#ifdef PNG_WRITE_sRGB_SUPPORTED
 /* Write a sRGB chunk */
 void /* PRIVATE */
 png_write_sRGB(png_structp png_ptr, int srgb_intent)
@@ -741,6 +754,7 @@ png_write_sRGB(png_structp png_ptr, int srgb_intent)
    png_byte buf[1];
 
    png_debug(1, "in png_write_sRGB");
+
    if (srgb_intent >= PNG_sRGB_INTENT_LAST)
          png_warning(png_ptr,
             "Invalid sRGB rendering intent specified");
@@ -749,7 +763,7 @@ png_write_sRGB(png_structp png_ptr, int srgb_intent)
 }
 #endif
 
-#if defined(PNG_WRITE_iCCP_SUPPORTED)
+#ifdef PNG_WRITE_iCCP_SUPPORTED
 /* Write an iCCP chunk */
 void /* PRIVATE */
 png_write_iCCP(png_structp png_ptr, png_charp name, int compression_type,
@@ -788,6 +802,14 @@ png_write_iCCP(png_structp png_ptr, png_charp name, int compression_type,
           ((*( (png_bytep)profile + 2))<< 8) |
           ((*( (png_bytep)profile + 3))    );
 
+   if (embedded_profile_len < 0)
+   {
+      png_warning(png_ptr,
+        "Embedded profile length in iCCP chunk is negative");
+      png_free(png_ptr, new_name);
+      return;
+   }
+
    if (profile_len < embedded_profile_len)
    {
       png_warning(png_ptr,
@@ -822,7 +844,7 @@ png_write_iCCP(png_structp png_ptr, png_charp name, int compression_type,
 }
 #endif
 
-#if defined(PNG_WRITE_sPLT_SUPPORTED)
+#ifdef PNG_WRITE_sPLT_SUPPORTED
 /* Write a sPLT chunk */
 void /* PRIVATE */
 png_write_sPLT(png_structp png_ptr, png_sPLT_tp spalette)
@@ -836,11 +858,12 @@ png_write_sPLT(png_structp png_ptr, png_sPLT_tp spalette)
    int entry_size = (spalette->depth == 8 ? 6 : 10);
    int palette_size = entry_size * spalette->nentries;
    png_sPLT_entryp ep;
-#ifdef PNG_NO_POINTER_INDEXING
+#ifndef PNG_POINTER_INDEXING_SUPPORTED
    int i;
 #endif
 
    png_debug(1, "in png_write_sPLT");
+
    if ((name_len = png_check_keyword(png_ptr,spalette->name, &new_name))==0)
       return;
 
@@ -852,7 +875,7 @@ png_write_sPLT(png_structp png_ptr, png_sPLT_tp spalette)
    png_write_chunk_data(png_ptr, (png_bytep)&spalette->depth, (png_size_t)1);
 
    /* Loop through each palette entry, writing appropriately */
-#ifndef PNG_NO_POINTER_INDEXING
+#ifdef PNG_POINTER_INDEXING_SUPPORTED
    for (ep = spalette->entries; ep<spalette->entries + spalette->nentries; ep++)
    {
       if (spalette->depth == 8)
@@ -902,7 +925,7 @@ png_write_sPLT(png_structp png_ptr, png_sPLT_tp spalette)
 }
 #endif
 
-#if defined(PNG_WRITE_sBIT_SUPPORTED)
+#ifdef PNG_WRITE_sBIT_SUPPORTED
 /* Write the sBIT chunk */
 void /* PRIVATE */
 png_write_sBIT(png_structp png_ptr, png_color_8p sbit, int color_type)
@@ -914,6 +937,7 @@ png_write_sBIT(png_structp png_ptr, png_color_8p sbit, int color_type)
    png_size_t size;
 
    png_debug(1, "in png_write_sBIT");
+
    /* Make sure we don't depend upon the order of PNG_COLOR_8 */
    if (color_type & PNG_COLOR_MASK_COLOR)
    {
@@ -958,7 +982,7 @@ png_write_sBIT(png_structp png_ptr, png_color_8p sbit, int color_type)
 }
 #endif
 
-#if defined(PNG_WRITE_cHRM_SUPPORTED)
+#ifdef PNG_WRITE_cHRM_SUPPORTED
 /* Write the cHRM chunk */
 #ifdef PNG_FLOATING_POINT_SUPPORTED
 void /* PRIVATE */
@@ -985,7 +1009,7 @@ png_write_cHRM(png_structp png_ptr, double white_x, double white_y,
    int_blue_x  = (png_uint_32)(blue_x  * 100000.0 + 0.5);
    int_blue_y  = (png_uint_32)(blue_y  * 100000.0 + 0.5);
 
-#if !defined(PNG_NO_CHECK_cHRM)
+#ifdef PNG_CHECK_cHRM_SUPPORTED
    if (png_check_cHRM_fixed(png_ptr, int_white_x, int_white_y,
       int_red_x, int_red_y, int_green_x, int_green_y, int_blue_x, int_blue_y))
 #endif
@@ -1021,8 +1045,9 @@ png_write_cHRM_fixed(png_structp png_ptr, png_fixed_point white_x,
    png_byte buf[32];
 
    png_debug(1, "in png_write_cHRM");
+
    /* Each value is saved in 1/100,000ths */
-#if !defined(PNG_NO_CHECK_cHRM)
+#ifdef PNG_CHECK_cHRM_SUPPORTED
    if (png_check_cHRM_fixed(png_ptr, white_x, white_y, red_x, red_y,
       green_x, green_y, blue_x, blue_y))
 #endif
@@ -1045,7 +1070,7 @@ png_write_cHRM_fixed(png_structp png_ptr, png_fixed_point white_x,
 #endif
 #endif
 
-#if defined(PNG_WRITE_tRNS_SUPPORTED)
+#ifdef PNG_WRITE_tRNS_SUPPORTED
 /* Write the tRNS chunk */
 void /* PRIVATE */
 png_write_tRNS(png_structp png_ptr, png_bytep trans, png_color_16p tran,
@@ -1057,6 +1082,7 @@ png_write_tRNS(png_structp png_ptr, png_bytep trans, png_color_16p tran,
    png_byte buf[6];
 
    png_debug(1, "in png_write_tRNS");
+
    if (color_type == PNG_COLOR_TYPE_PALETTE)
    {
       if (num_trans <= 0 || num_trans > (int)png_ptr->num_palette)
@@ -1101,7 +1127,7 @@ png_write_tRNS(png_structp png_ptr, png_bytep trans, png_color_16p tran,
 }
 #endif
 
-#if defined(PNG_WRITE_bKGD_SUPPORTED)
+#ifdef PNG_WRITE_bKGD_SUPPORTED
 /* Write the background chunk */
 void /* PRIVATE */
 png_write_bKGD(png_structp png_ptr, png_color_16p back, int color_type)
@@ -1112,10 +1138,11 @@ png_write_bKGD(png_structp png_ptr, png_color_16p back, int color_type)
    png_byte buf[6];
 
    png_debug(1, "in png_write_bKGD");
+
    if (color_type == PNG_COLOR_TYPE_PALETTE)
    {
       if (
-#if defined(PNG_MNG_FEATURES_SUPPORTED)
+#ifdef PNG_MNG_FEATURES_SUPPORTED
           (png_ptr->num_palette ||
           (!(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE))) &&
 #endif
@@ -1154,7 +1181,7 @@ png_write_bKGD(png_structp png_ptr, png_color_16p back, int color_type)
 }
 #endif
 
-#if defined(PNG_WRITE_hIST_SUPPORTED)
+#ifdef PNG_WRITE_hIST_SUPPORTED
 /* Write the histogram */
 void /* PRIVATE */
 png_write_hIST(png_structp png_ptr, png_uint_16p hist, int num_hist)
@@ -1166,6 +1193,7 @@ png_write_hIST(png_structp png_ptr, png_uint_16p hist, int num_hist)
    png_byte buf[3];
 
    png_debug(1, "in png_write_hIST");
+
    if (num_hist > (int)png_ptr->num_palette)
    {
       png_debug2(3, "num_hist = %d, num_palette = %d", num_hist,
@@ -1206,6 +1234,7 @@ png_check_keyword(png_structp png_ptr, png_charp key, png_charpp new_key)
    int kwarn=0;
 
    png_debug(1, "in png_check_keyword");
+
    *new_key = NULL;
 
    if (key == NULL || (key_len = png_strlen(key)) == 0)
@@ -1229,7 +1258,7 @@ png_check_keyword(png_structp png_ptr, png_charp key, png_charpp new_key)
       if ((png_byte)*kp < 0x20 ||
          ((png_byte)*kp > 0x7E && (png_byte)*kp < 0xA1))
       {
-#if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
+#if defined(PNG_STDIO_SUPPORTED) && !defined(_WIN32_WCE)
          char msg[40];
 
          png_snprintf(msg, 40,
@@ -1316,7 +1345,7 @@ png_check_keyword(png_structp png_ptr, png_charp key, png_charpp new_key)
 }
 #endif
 
-#if defined(PNG_WRITE_tEXt_SUPPORTED)
+#ifdef PNG_WRITE_tEXt_SUPPORTED
 /* Write a tEXt chunk */
 void /* PRIVATE */
 png_write_tEXt(png_structp png_ptr, png_charp key, png_charp text,
@@ -1329,6 +1358,7 @@ png_write_tEXt(png_structp png_ptr, png_charp key, png_charp text,
    png_charp new_key;
 
    png_debug(1, "in png_write_tEXt");
+
    if ((key_len = png_check_keyword(png_ptr, key, &new_key))==0)
       return;
 
@@ -1356,7 +1386,7 @@ png_write_tEXt(png_structp png_ptr, png_charp key, png_charp text,
 }
 #endif
 
-#if defined(PNG_WRITE_zTXt_SUPPORTED)
+#ifdef PNG_WRITE_zTXt_SUPPORTED
 /* Write a compressed text chunk */
 void /* PRIVATE */
 png_write_zTXt(png_structp png_ptr, png_charp key, png_charp text,
@@ -1416,7 +1446,7 @@ png_write_zTXt(png_structp png_ptr, png_charp key, png_charp text,
 }
 #endif
 
-#if defined(PNG_WRITE_iTXt_SUPPORTED)
+#ifdef PNG_WRITE_iTXt_SUPPORTED
 /* Write an iTXt chunk */
 void /* PRIVATE */
 png_write_iTXt(png_structp png_ptr, int compression, png_charp key,
@@ -1505,7 +1535,7 @@ png_write_iTXt(png_structp png_ptr, int compression, png_charp key,
 }
 #endif
 
-#if defined(PNG_WRITE_oFFs_SUPPORTED)
+#ifdef PNG_WRITE_oFFs_SUPPORTED
 /* Write the oFFs chunk */
 void /* PRIVATE */
 png_write_oFFs(png_structp png_ptr, png_int_32 x_offset, png_int_32 y_offset,
@@ -1517,6 +1547,7 @@ png_write_oFFs(png_structp png_ptr, png_int_32 x_offset, png_int_32 y_offset,
    png_byte buf[9];
 
    png_debug(1, "in png_write_oFFs");
+
    if (unit_type >= PNG_OFFSET_LAST)
       png_warning(png_ptr, "Unrecognized unit type for oFFs chunk");
 
@@ -1527,7 +1558,7 @@ png_write_oFFs(png_structp png_ptr, png_int_32 x_offset, png_int_32 y_offset,
    png_write_chunk(png_ptr, (png_bytep)png_oFFs, buf, (png_size_t)9);
 }
 #endif
-#if defined(PNG_WRITE_pCAL_SUPPORTED)
+#ifdef PNG_WRITE_pCAL_SUPPORTED
 /* Write the pCAL chunk (described in the PNG extensions document) */
 void /* PRIVATE */
 png_write_pCAL(png_structp png_ptr, png_charp purpose, png_int_32 X0,
@@ -1543,6 +1574,7 @@ png_write_pCAL(png_structp png_ptr, png_charp purpose, png_int_32 X0,
    int i;
 
    png_debug1(1, "in png_write_pCAL (%d parameters)", nparams);
+
    if (type >= PNG_EQUATION_LAST)
       png_warning(png_ptr, "Unrecognized equation type for pCAL chunk");
 
@@ -1589,9 +1621,9 @@ png_write_pCAL(png_structp png_ptr, png_charp purpose, png_int_32 X0,
 }
 #endif
 
-#if defined(PNG_WRITE_sCAL_SUPPORTED)
+#ifdef PNG_WRITE_sCAL_SUPPORTED
 /* Write the sCAL chunk */
-#if defined(PNG_FLOATING_POINT_SUPPORTED) && !defined(PNG_NO_STDIO)
+#if defined(PNG_FLOATING_POINT_SUPPORTED) && defined(PNG_STDIO_SUPPORTED)
 void /* PRIVATE */
 png_write_sCAL(png_structp png_ptr, int unit, double width, double height)
 {
@@ -1604,14 +1636,15 @@ png_write_sCAL(png_structp png_ptr, int unit, double width, double height)
    png_debug(1, "in png_write_sCAL");
 
    buf[0] = (char)unit;
-#if defined(_WIN32_WCE)
+#ifdef _WIN32_WCE
 /* sprintf() function is not supported on WindowsCE */
    {
       wchar_t wc_buf[32];
       size_t wc_len;
       swprintf(wc_buf, TEXT("%12.12e"), width);
       wc_len = wcslen(wc_buf);
-      WideCharToMultiByte(CP_ACP, 0, wc_buf, -1, buf + 1, wc_len, NULL, NULL);
+      WideCharToMultiByte(CP_ACP, 0, wc_buf, -1, buf + 1, wc_len, NULL,
+          NULL);
       total_len = wc_len + 2;
       swprintf(wc_buf, TEXT("%12.12e"), height);
       wc_len = wcslen(wc_buf);
@@ -1663,7 +1696,7 @@ png_write_sCAL_s(png_structp png_ptr, int unit, png_charp width,
 #endif
 #endif
 
-#if defined(PNG_WRITE_pHYs_SUPPORTED)
+#ifdef PNG_WRITE_pHYs_SUPPORTED
 /* Write the pHYs chunk */
 void /* PRIVATE */
 png_write_pHYs(png_structp png_ptr, png_uint_32 x_pixels_per_unit,
@@ -1676,6 +1709,7 @@ png_write_pHYs(png_structp png_ptr, png_uint_32 x_pixels_per_unit,
    png_byte buf[9];
 
    png_debug(1, "in png_write_pHYs");
+
    if (unit_type >= PNG_RESOLUTION_LAST)
       png_warning(png_ptr, "Unrecognized unit type for pHYs chunk");
 
@@ -1687,7 +1721,7 @@ png_write_pHYs(png_structp png_ptr, png_uint_32 x_pixels_per_unit,
 }
 #endif
 
-#if defined(PNG_WRITE_tIME_SUPPORTED)
+#ifdef PNG_WRITE_tIME_SUPPORTED
 /* Write the tIME chunk.  Use either png_convert_from_struct_tm()
  * or png_convert_from_time_t(), or fill in the structure yourself.
  */
@@ -1700,6 +1734,7 @@ png_write_tIME(png_structp png_ptr, png_timep mod_time)
    png_byte buf[7];
 
    png_debug(1, "in png_write_tIME");
+
    if (mod_time->month  > 12 || mod_time->month  < 1 ||
        mod_time->day    > 31 || mod_time->day    < 1 ||
        mod_time->hour   > 23 || mod_time->second > 60)
@@ -1724,7 +1759,6 @@ void /* PRIVATE */
 png_write_start_row(png_structp png_ptr)
 {
 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
-#ifdef PNG_USE_LOCAL_ARRAYS
    /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
 
    /* Start of interlace block */
@@ -1739,11 +1773,11 @@ png_write_start_row(png_structp png_ptr)
    /* Offset to next interlace block in the y direction */
    int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
 #endif
-#endif
 
    png_size_t buf_size;
 
    png_debug(1, "in png_write_start_row");
+
    buf_size = (png_size_t)(PNG_ROWBYTES(
       png_ptr->usr_channels*png_ptr->usr_bit_depth, png_ptr->width) + 1);
 
@@ -1752,7 +1786,7 @@ png_write_start_row(png_structp png_ptr)
      (png_uint_32)buf_size);
    png_ptr->row_buf[0] = PNG_FILTER_VALUE_NONE;
 
-#ifndef PNG_NO_WRITE_FILTER
+#ifdef PNG_WRITE_FILTER_SUPPORTED
    /* Set up filtering buffer, if using this filter */
    if (png_ptr->do_filter & PNG_FILTER_SUB)
    {
@@ -1764,33 +1798,32 @@ png_write_start_row(png_structp png_ptr)
    /* We only need to keep the previous row if we are using one of these. */
    if (png_ptr->do_filter & (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH))
    {
-     /* Set up previous row buffer */
-     png_ptr->prev_row = (png_bytep)png_malloc(png_ptr,
-        (png_uint_32)buf_size);
-     png_memset(png_ptr->prev_row, 0, buf_size);
+      /* Set up previous row buffer */
+      png_ptr->prev_row = (png_bytep)png_calloc(png_ptr,
+         (png_uint_32)buf_size);
 
       if (png_ptr->do_filter & PNG_FILTER_UP)
       {
          png_ptr->up_row = (png_bytep)png_malloc(png_ptr,
-           (png_uint_32)(png_ptr->rowbytes + 1));
+            (png_uint_32)(png_ptr->rowbytes + 1));
          png_ptr->up_row[0] = PNG_FILTER_VALUE_UP;
       }
 
       if (png_ptr->do_filter & PNG_FILTER_AVG)
       {
          png_ptr->avg_row = (png_bytep)png_malloc(png_ptr,
-           (png_uint_32)(png_ptr->rowbytes + 1));
+            (png_uint_32)(png_ptr->rowbytes + 1));
          png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG;
       }
 
       if (png_ptr->do_filter & PNG_FILTER_PAETH)
       {
          png_ptr->paeth_row = (png_bytep)png_malloc(png_ptr,
-           (png_uint_32)(png_ptr->rowbytes + 1));
+            (png_uint_32)(png_ptr->rowbytes + 1));
          png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH;
       }
    }
-#endif /* PNG_NO_WRITE_FILTER */
+#endif /* PNG_WRITE_FILTER_SUPPORTED */
 
 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
    /* If interlaced, we need to set up width and height of pass */
@@ -1824,7 +1857,6 @@ void /* PRIVATE */
 png_write_finish_row(png_structp png_ptr)
 {
 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
-#ifdef PNG_USE_LOCAL_ARRAYS
    /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
 
    /* Start of interlace block */
@@ -1839,11 +1871,11 @@ png_write_finish_row(png_structp png_ptr)
    /* Offset to next interlace block in the y direction */
    int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
 #endif
-#endif
 
    int ret;
 
    png_debug(1, "in png_write_finish_row");
+
    /* Next row */
    png_ptr->row_number++;
 
@@ -1931,7 +1963,7 @@ png_write_finish_row(png_structp png_ptr)
    png_ptr->zstream.data_type = Z_BINARY;
 }
 
-#if defined(PNG_WRITE_INTERLACING_SUPPORTED)
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
 /* Pick out the correct pixels for the interlace pass.
  * The basic idea here is to go through the row with a source
  * pointer and a destination pointer (sp and dp), and copy the
@@ -1942,7 +1974,6 @@ png_write_finish_row(png_structp png_ptr)
 void /* PRIVATE */
 png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
 {
-#ifdef PNG_USE_LOCAL_ARRAYS
    /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
 
    /* Start of interlace block */
@@ -1950,11 +1981,11 @@ png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
 
    /* Offset to next interlace block */
    int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
-#endif
 
    png_debug(1, "in png_do_write_interlace");
+
    /* We don't have to do anything on the last pass (6) */
-#if defined(PNG_USELESS_TESTS_SUPPORTED)
+#ifdef PNG_USELESS_TESTS_SUPPORTED
    if (row != NULL && row_info != NULL && pass < 6)
 #else
    if (pass < 6)
@@ -2114,23 +2145,32 @@ void /* PRIVATE */
 png_write_find_filter(png_structp png_ptr, png_row_infop row_info)
 {
    png_bytep best_row;
-#ifndef PNG_NO_WRITE_FILTER
+#ifdef PNG_WRITE_FILTER_SUPPORTED
    png_bytep prev_row, row_buf;
    png_uint_32 mins, bpp;
    png_byte filter_to_do = png_ptr->do_filter;
    png_uint_32 row_bytes = row_info->rowbytes;
-#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
    int num_p_filters = (int)png_ptr->num_prev_filters;
-#endif
+#endif 
 
    png_debug(1, "in png_write_find_filter");
+
+#ifndef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
+  if (png_ptr->row_number == 0 && filter_to_do == PNG_ALL_FILTERS)
+  {
+      /* These will never be selected so we need not test them. */
+      filter_to_do &= ~(PNG_FILTER_UP | PNG_FILTER_PAETH);
+  }
+#endif 
+
    /* Find out how many bytes offset each pixel is */
    bpp = (row_info->pixel_depth + 7) >> 3;
 
    prev_row = png_ptr->prev_row;
 #endif
    best_row = png_ptr->row_buf;
-#ifndef PNG_NO_WRITE_FILTER
+#ifdef PNG_WRITE_FILTER_SUPPORTED
    row_buf = best_row;
    mins = PNG_MAXSUM;
 
@@ -2173,7 +2213,7 @@ png_write_find_filter(png_structp png_ptr, png_row_infop row_info)
          sum += (v < 128) ? v : 256 - v;
       }
 
-#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
       if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
       {
          png_uint_32 sumhi, sumlo;
@@ -2237,7 +2277,7 @@ png_write_find_filter(png_structp png_ptr, png_row_infop row_info)
       png_uint_32 i;
       int v;
 
-#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
       /* We temporarily increase the "minimum sum" by the factor we
        * would reduce the sum of this filter, so that we can do the
        * early exit comparison without scaling the sum each time.
@@ -2290,7 +2330,7 @@ png_write_find_filter(png_structp png_ptr, png_row_infop row_info)
             break;
       }
 
-#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
       if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
       {
          int j;
@@ -2351,7 +2391,7 @@ png_write_find_filter(png_structp png_ptr, png_row_infop row_info)
       int v;
 
 
-#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
       if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
       {
          int j;
@@ -2393,7 +2433,7 @@ png_write_find_filter(png_structp png_ptr, png_row_infop row_info)
             break;
       }
 
-#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
       if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
       {
          int j;
@@ -2456,7 +2496,7 @@ png_write_find_filter(png_structp png_ptr, png_row_infop row_info)
       png_uint_32 i;
       int v;
 
-#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
       if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
       {
          int j;
@@ -2505,7 +2545,7 @@ png_write_find_filter(png_structp png_ptr, png_row_infop row_info)
             break;
       }
 
-#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
       if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
       {
          int j;
@@ -2589,7 +2629,7 @@ png_write_find_filter(png_structp png_ptr, png_row_infop row_info)
       png_uint_32 i;
       int v;
 
-#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
       if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
       {
          int j;
@@ -2670,7 +2710,7 @@ png_write_find_filter(png_structp png_ptr, png_row_infop row_info)
             break;
       }
 
-#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
       if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
       {
          int j;
@@ -2706,13 +2746,13 @@ png_write_find_filter(png_structp png_ptr, png_row_infop row_info)
          best_row = png_ptr->paeth_row;
       }
    }
-#endif /* PNG_NO_WRITE_FILTER */
+#endif /* PNG_WRITE_FILTER_SUPPORTED */
    /* Do the actual writing of the filtered row data from the chosen filter. */
 
    png_write_filtered_row(png_ptr, best_row);
 
-#ifndef PNG_NO_WRITE_FILTER
-#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
    /* Save the type of filter we picked this time for future calculations */
    if (png_ptr->num_prev_filters > 0)
    {
@@ -2724,7 +2764,7 @@ png_write_find_filter(png_structp png_ptr, png_row_infop row_info)
       png_ptr->prev_filters[j] = best_row[0];
    }
 #endif
-#endif /* PNG_NO_WRITE_FILTER */
+#endif /* PNG_WRITE_FILTER_SUPPORTED */
 }
 
 
@@ -2733,6 +2773,7 @@ void /* PRIVATE */
 png_write_filtered_row(png_structp png_ptr, png_bytep filtered_row)
 {
    png_debug(1, "in png_write_filtered_row");
+
    png_debug1(2, "filter = %d", filtered_row[0]);
    /* Set up the zlib input buffer */
 
@@ -2778,7 +2819,7 @@ png_write_filtered_row(png_structp png_ptr, png_bytep filtered_row)
    /* Finish row - updates counters and flushes zlib if last row */
    png_write_finish_row(png_ptr);
 
-#if defined(PNG_WRITE_FLUSH_SUPPORTED)
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
    png_ptr->flush_rows++;
 
    if (png_ptr->flush_dist > 0 &&